Allow merge failures to have unique reporters.

For example, we would like to be able to count (with the MySQL
reporter) what jobs have failed because they can't be merged
vs. real failures.

Change-Id: I98eb8b8817bbda57efc2ef5bfcc2a5076fe8f4fd
diff --git a/tests/fixtures/layouts/bad_merge_failure.yaml b/tests/fixtures/layouts/bad_merge_failure.yaml
new file mode 100644
index 0000000..313d23b
--- /dev/null
+++ b/tests/fixtures/layouts/bad_merge_failure.yaml
@@ -0,0 +1,39 @@
+pipelines:
+  - name: check
+    manager: IndependentPipelineManager
+    trigger:
+      gerrit:
+        - event: patchset-created
+    success:
+      gerrit:
+        verified: 1
+    failure:
+      gerrit:
+        verified: -1
+    merge-failure-message:
+
+  - name: gate
+    manager: DependentPipelineManager
+    failure-message: Build failed.  For information on how to proceed, see http://wiki.example.org/Test_Failures
+    trigger:
+      gerrit:
+        - event: comment-added
+          approval:
+            - approved: 1
+    success:
+      gerrit:
+        verified: 2
+        submit: true
+    failure:
+      gerrit:
+        verified: -2
+    merge-failure:
+    start:
+      gerrit:
+        verified: 0
+    precedence: high
+
+projects:
+  - name: org/project
+    check:
+      - project-check